package com.jeeww.lucene.demo;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
 * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
 * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
 * applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */

import java.io.Closeable;
import java.io.IOException;

import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.LongField;
import org.apache.lucene.document.NumericDocValuesField;
import org.apache.lucene.facet.DrillDownQuery;
import org.apache.lucene.facet.FacetResult;
import org.apache.lucene.facet.Facets;
import org.apache.lucene.facet.FacetsCollector;
import org.apache.lucene.facet.FacetsConfig;
import org.apache.lucene.facet.range.LongRange;
import org.apache.lucene.facet.range.LongRangeFacetCounts;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.NumericRangeQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;

/** Shows simple usage of dynamic range faceting. */
public class RangeFacetsExample implements Closeable {

    private final Directory indexDir = new RAMDirectory();
    private IndexSearcher searcher;
    private final long nowSec = System.currentTimeMillis();

    final LongRange PAST_HOUR = new LongRange("Past hour", nowSec - 3600, true, nowSec, true);
    final LongRange PAST_SIX_HOURS = new LongRange("Past six hours", nowSec - 6 * 3600, true, nowSec, true);
    final LongRange PAST_DAY = new LongRange("Past day", nowSec - 24 * 3600, true, nowSec, true);

    /** Empty constructor */
    public RangeFacetsExample() {
    }

    /** Build the example index. */
    public void index() throws IOException {
        IndexWriter indexWriter = new IndexWriter(indexDir, new IndexWriterConfig(FacetExamples.EXAMPLES_VER,
                new WhitespaceAnalyzer(FacetExamples.EXAMPLES_VER)));

        // Add documents with a fake timestamp, 1000 sec before
        // "now", 2000 sec before "now", ...:
        for (int i = 0; i < 100; i++) {
            Document doc = new Document();
            long then = nowSec - i * 1000;
            // Add as doc values field, so we can compute range facets:
            doc.add(new NumericDocValuesField("timestamp", then));
            // Add as numeric field so we can drill-down:
            doc.add(new LongField("timestamp", then, Field.Store.NO));
            indexWriter.addDocument(doc);
        }

        // Open near-real-time searcher
        searcher = new IndexSearcher(DirectoryReader.open(indexWriter, true));
        indexWriter.close();
    }

    private FacetsConfig getConfig() {
        return new FacetsConfig();
    }

    /** User runs a query and counts facets. */
    public FacetResult search() throws IOException {

        // Aggregates the facet counts
        FacetsCollector fc = new FacetsCollector();

        // MatchAllDocsQuery is for "browsing" (counts facets
        // for all non-deleted docs in the index); normally
        // you'd use a "normal" query:
        FacetsCollector.search(searcher, new MatchAllDocsQuery(), 10, fc);

        Facets facets = new LongRangeFacetCounts("timestamp", fc, PAST_HOUR, PAST_SIX_HOURS, PAST_DAY);
        return facets.getTopChildren(10, "timestamp");
    }

    /** User drills down on the specified range. */
    public TopDocs drillDown(LongRange range) throws IOException {

        // Passing no baseQuery means we drill down on all
        // documents ("browse only"):
        DrillDownQuery q = new DrillDownQuery(getConfig());

        q.add("timestamp", NumericRangeQuery.newLongRange("timestamp", range.min, range.max, range.minInclusive,
                range.maxInclusive));

        return searcher.search(q, 10);
    }

    @Override
    public void close() throws IOException {
        searcher.getIndexReader().close();
        indexDir.close();
    }

    /** Runs the search and drill-down examples and prints the results. */
    @SuppressWarnings("unchecked")
    public static void main(String[] args) throws Exception {
        RangeFacetsExample example = new RangeFacetsExample();
        example.index();

        System.out.println("Facet counting example:");
        System.out.println("-----------------------");
        System.out.println(example.search());

        System.out.println("\n");
        System.out.println("Facet drill-down example (timestamp/Past six hours):");
        System.out.println("---------------------------------------------");
        TopDocs hits = example.drillDown(example.PAST_SIX_HOURS);
        System.out.println(hits.totalHits + " totalHits");

        example.close();
    }
}
